Generality
Lewy body dementia is the third most common form of dementia in humans, after Alzheimer's disease and vascular dementia.
Its particular name derives from the fact that insoluble protein aggregates called Lewy bodies are formed inside some neurons of the brain.
Diagnosing Lewy body dementia is not easy; the doctor is based on an "accurate evaluation of the symptoms (which is very varied), on some diagnostic imaging tests (CT and magnetic resonance imaging) and on tests that exclude pathologies from similar disorders.
Unfortunately, Lewy body dementia is an incurable and life-threatening disease.
What is Lewy body dementia?
Lewy body dementia (or Lewy body dementia) is a neurodegenerative disease of the brain, which causes a progressive decline in a person's cognition.
Its name derives from the unusual presence, in the cells of the cerebral cortex and of the substantia nigra of patients, of insoluble protein aggregates called Lewy bodies.
Made up of a protein known as alpha-synuclein, Lewy bodies are the same abnormal clusters found within the neurons of people with Parkinson's disease and multi-system atrophy.
The substantia nigra
There substantia nigra - also known as Sommering's black substance - is a particular area of the brain located between the midbrain and the diencephalon, near the cerebral peduncles.
In substantia nigra two regions can be recognized: the so-called pars compacta (or compact part) and the so-called pars reticulata (or cross-linked part).
With different specific functions, these two regions provide for the execution and control of various motor functions.
EPIDEMIOGY
Lewy body dementia accounts for 10-15% of all known forms of dementia and, by spread, comes soon after Alzheimer's disease (by far the most common dementia, with 50-70 in every 100 cases of dementia) and vascular dementia (with about 25 cases in 100).
Lewy body dementia affects both sexes with the same incidence and, like most dementias, occurs more frequently in people aged 65 and over (hence it is more common in old age).
Causes
Like many forms of dementia, Lewy body dementia also arises because neurons in the brain die or fail to function as they should.
Although the studies in this regard still present some question marks, the researchers believe that the aforementioned Lewy bodies formed in the cytoplasm of the latter cause the death (or malfunction) of brain cells.
ASPECTS TO CLARIFY
On the role played by Lewy bodies, doctors and researchers have yet to clarify at least two aspects:
- What causes it to form at some point in a person's life;
- How they damage the neurons that contain them.
Regarding this second point, there is a "hypothesis - still not scientifically proven - according to which the Lewy bodies would interfere with the chemical signaling between the neurons of the cerebral cortex and those of the substantia nigra; chemical signaling which has among its main actors molecules called, in general, neurotransmitters.
RISK FACTORS
After various studies, doctors and researchers have concluded that the conditions that favor the onset of Lewy body dementia - or risk factors - are:
- The advanced age
- A certain family predisposition to the disease.
Specific genetic mutations have been identified which - if passed from a parent to a child - increase the chance of developing dementia. However, scientists are keen to point out that these genetic anomalies are very rare.
Symptoms and Complications
Like other forms of dementia, Lewy body disease is responsible for mild symptoms only in the initial phase. In fact, as the involvement of brain neurons becomes more and more extensive, the disturbances and alterations of cognitive abilities tend to worsen inexorably. Moreover, in the final stages of the disease it is impossible to carry out even the simplest daily chores.
Although each patient represents a separate case, the manifestations of Lewy body dementia are usually a mixture of the symptoms of Alzheimer's and the symptoms of Parkinson's disease.
Going therefore into the details, the symptomatic picture includes:
- Problems of attention and vigilance.
They are very common and somewhat fickle ailments. In fact, they tend to vary from hour to hour, alternating sudden improvements with equally sudden worsening. - Problems with three-dimensional perception and in quantifying the distances of objects.
- Difficulty in judgment, planning and thinking.
- Memory loss.
It is a more common ailment in the late stages of the disease. - Visual hallucinations, i.e. seeing things that don't exist.
They are very frequent. - Auditory hallucinations, i.e. hearing non-existent things.
They are less common than the previous ones. - Motor problems, which follow the typical symptoms of Parkinson's disease.
Among the most common manifestations are stiffness and slowing of movements, blank expression of the face, sleepiness, bent gait when walking, shuffling, precarious balance and tremors in the limbs.
The typical symptoms of Parkinson's disease affect about 2/3 of people with dementia from Lewy bodies and are responsible for falls and temporary loss of consciousness.
The more advanced the dementia is, the more severe all these disorders are. - Particular sleep disturbances, which lead the patient to fall asleep during the day and to feel restless at night, with difficulty in falling asleep.
- Confusion
- Depression
- Speech problems
- Problems with chewing and swallowing.
These disorders are particularly pronounced in the final stages of the disease and are possible causes of inhalation pneumonia or episodes of suffocation.
HOW ARE THE SYMPTOMS OF PARKINSON EXPLAINED?
HOW LONG DOES A PATIENT LIVE AFTER THE FIRST SYMPTOM?
Although each patient represents a case of its own, individuals with Lewy body dementia typically live about 7-8 years after the first symptom appeared.
WHEN TO SEE THE DOCTOR?
Doctors recommend contacting them as soon as the first signs of dementia appear.
This serves to reduce the impact the disease can have on the patient as it becomes more and more severe.
Diagnosis
Diagnosing Lewy body dementia is complex for at least a couple of reasons:
- The similarity of symptoms to those of other forms of dementia (Alzheimer's disease in particular).
- The lack of an examination or instrumental test that specifically recognizes such dementia. This often leads doctors to proceed by exclusion (differential diagnosis).
Typically, the diagnostic workup for a suspected case of Lewy dementia involves a number of different assessments, including:
- A medical history analysis, followed by a careful physical examination.
- A neurological exam
- An "analysis of mental abilities
- Laboratory tests
- A magnetic resonance imaging (MRI) and / or a CT scan (computed axial tomography), both referred to the brain.
CLINICAL HISTORY AND OBJECTIVE EXAMINATION
The clinical history analysis is a medical investigation aimed at clarifying how and when the first disorders appeared, if the patient suffers or has suffered in the past from particular pathologies, if he takes certain drugs, etc.
The most important symptoms:
- Lack of attention and vigilance
- Visual hallucinations
- Typical symptoms of Parkinson's disease
The objective examination, on the other hand, is the observation and collection of the symptoms manifested (or complained of) by the patient.
In both cases, it is of particular importance to also question a close relative of the patient (or a person who spends a lot of time with him), in order to obtain a more detailed symptom picture.
NEUROLOGICAL EXAMINATION AND MENTAL SKILLS
The neurological examination consists of an analysis of tendon reflexes, motor skills (balance, etc.) and sensory functions.
The assessment of mental abilities, on the other hand, involves the study of cognitive abilities (i.e. reasoning, judgment, language, etc.) and their degree of impairment.
For a physician experienced in Lewy body dementia, two such investigations can provide vital information.
LABORATORY EXAMS
Among the laboratory tests, the following should be noted in particular:
- Blood tests
- Urinalysis
- Toxicological tests
- The measurement of blood sugar
Their execution serves, more than anything else, from a differential diagnosis perspective, therefore to exclude morbid conditions from similar symptoms. For example, blood tests allow us to rule out the hypothesis that the disorders are related to a vitamin B12 deficiency.
MRI AND CT
Nuclear magnetic resonance and CT are two diagnostic imaging tests, which allow you to:
- Evaluate the presence of tumors, strokes and brain hemorrhages. Verifying that these conditions are not involved is very important information in view of the final diagnosis.
- Observe the appearance of the brain area identified with the term substantia nigra. In the case of Lewy body dementia, this particular portion of the brain is singularly altered.
Treatment
Like most dementias, Lewy body disease is a neurodegenerative disease from which, according to current medical knowledge, it is impossible to cure. However, there are treatments capable of reducing symptoms and improving, albeit to a limited extent, the health conditions of sick individuals (symptomatic therapy).
DRUGS FOR SYMPTOMATIC THERAPY
With different efficacy from patient to patient, the drugs used in Lewy body dementia are:
- Acetylcholinesterase inhibitors.
Medicines belonging to this category which may be effective against hallucinations, confusion and somnolence are donepezil, galantamine and rivastigmine.
Side effects: feeling sick, diarrhea, headache, recurring fatigue and muscle cramps. - Levodopa.
It aims to reduce parkinsonian symptoms, hence movement problems.
Side effects: worsens hallucinations. - Antidepressants.
They are used in those cases of Lewy body dementia marked by depression. - Clonazepam.
In some individuals, it relieves sleep disorders - Antipsychotics, especially haloperidol.
They are rarely administered and in low doses (because they are responsible for serious side effects), when the patient reports severe difficulties in judgment.
Side effects: can cause stiffness and immobility
OTHER TREATMENTS THAT ARE PART OF THE SYMPTOMATIC THERAPY
- Physiotherapy. It is used to improve motor disorders and balance problems.
- Occupational therapy. Its goal is to make the patient as independent as possible from others and to re-insert him into a social context.
- Language therapy. It serves to relieve speech disorders (which affect communication skills) and to improve swallowing skills.
- Cognitive stimulation. It includes exercises aimed at improving memory, language and thinking skills.
- Correction of vision problems. It can be a partial remedy for the visual hallucinations that patients usually suffer.
- A light physical activity (a simple walk is enough) and the refusal of any kind of alcoholic beverages, cigarette smoke and coffee. These suggestions (N.B: for the first, a person must follow the patient step by step) are given to improve night sleep.
